Marking brake linings

ABSTRACT

The present invention relates to marking friction linings for drum brakes or for single-block brake pads in which the friction lining and the support member are made together by moulding a single material. According to the invention, the back of the friction lining or the back of the single-block brake pad is provided with an insert that is not oxidizable and that withstands a temperature of greater than 200° C., the insert having a surface that is visible outside the lining or the pad and that is suitable for acting as a medium to carry indelible information. Advantageously, the insert is in the form of a tongue, that projects towards the top of the brake calliper.

TECHNICAL FIELD

The present invention relates to indelibly marking brake linings fordrum brakes or for disk brakes.

BACKGROUND

At present, friction linings for drum brakes are marked either by inkjet marking directly on the lining or on a colour background previouslydeposited on the lining, or by marking using a transfer, or else byindentation by pressing a punch against the lining, in which case if itis desired for the marking to be coloured, a colour deposit film may beplaced between the punch and the brake lining.

Marking is performed either on the edge of the brake lining or else onits concave back face which is subsequently in contact with the brakelining support member in the caliper of the drum brake.

Such marking serves to identify a new friction lining, but it cannotguarantee that a friction lining will continue to be identifiablethroughout its lifetime, and in particular it cannot guarantee that theorigin of a used lining can be determined.

The present invention also relates to marking single-block brake padswhich do not include a metal support member on which the friction liningis secured.

FR-A-2,441,100 relates to such a brake pad made by moulding a preformfor the support member out of organic material and a preform for thebrake lining, and in which a metal reinforcing member is incorporated inthe support member. That document represents the state of the artclosest to the present invention. However, in that document the functionof the reinforcing member is to stiffen the support member which is madeof organic material.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a unique,unfalsifiable identification for a friction brake lining, or for asingle-block brake pad, which identification lasts throughout thelifetime of the lining or pad, including after a possible accident.

According to the invention, this object is achieved by the fact that thefriction lining includes, in an unused portion thereof, an insert thatis not oxidisable and that withstands temperatures greater than 200° C.,said insert having a surface that is visible from outside the pad andthat is suitable for serving as a medium for carrying indelibleinformation.

With a single-block brake pad, the insert is located in the rear portionof the pad which performs the support member or backplate function. Theinsert is then advantageously in the form of a tongue located on theback of the brake pad and projecting towards the top of the brakecaliper. The tongue enables the pad to be extracted when worn out.

A particularly preferred insert material is stainless steel, althoughother materials such as brass may be used.

Other advantages and characteristics of the invention will be apparentfrom the following description given by way of example with reference tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a single-block pad for a disk brake andfitted with an insert of the invention,

FIG. 2 is a view of the friction face of the brake pad of FIG. 1,

FIG. 3 is an end view of the FIG. 1 brake pad,

FIG. 4 is a plan view of the FIG. 1 brake pad,

FIG. 5 shows a method of positioning inserts on a trough-shaped preform,

FIG. 6 shows another method of positioning inserts on a friction liningpreform,

FIG. 7 shows a variant of the FIG. 5 method; and

FIGS. 8 and 9 show a method of fixing an insert on a friction lining fora drum brake while said lining is being machined.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 to 4 show a single-block brake pad 1 made by moulding material inthe form of a uniform powder mixture, the pad has at friction front face2 designed to co-operate with a rotary part forming a portion of abrake, and a rear face 3 co-operating with a caliper.

The front portion 4 of the pad 1 acts as a brake lining that is worndown by the rotary part, while the rear portion 5 acts as a supportmember co-operating with the caliper to take up the braking torque. Astainless steel insert 6 is secured to the rear portion 5 of the pad 1.The insert 6 has a surface 6a that is visible outside the pad 1 and onwhich it is possible to engrave indelible information making the pad 1traceable even in the event of the front portion 4 that forms the brakelining being worn away.

In the embodiment of FIGS. 1 to 4, the insert 6 is in the form of athin, narrow strip having a portion locating in the rear portion 5 andhaving its remainder in the form of a tongue 7 that projects upwards inthe brake caliper and that enables the brake pad 1 to be extracted whenworn. The tongue 7 can be used to carry information enabling the pad tobe uniquely identified.

The insert 6 may be flush with the surface of the pad 1 or it may be setinto a recess in the pad. What matters is that the insert always has asurface 6a that is visible from the outside of the pad 1.

The insert 6 may be installed during a preforming operation thatprecedes the final moulding operation, or else during the operation ofmoulding the lining, or indeed during the final operation of machiningthe lining.

If it is installed during the preforming operation, the insert may beapplied manually on the friction lining preform or on the single-blockpad preform, or it may be applied automatically by the piston of thepreforming press.

When the preforms 10 are trough-shaped, it is possible to use a mask 11that is trough-shaped and that has openings 12 for positioning inserts 6in such a manner that after moulding and cutting into individuallinings, each lining has its own insert 6, as can be seen in FIG. 5. Theinserts 6 may also be pre-stuck on a sheet 13 that is placed in thepreforming mould 14 after the friction substance has been placedtherein, as shown in FIG. 6. Instead of using separate inserts 6, it ispossible to use a continuous strip 15 that is narrow and thin and thatruns along one of the generator lines of the trough-shaped preform 10(FIG. 7), said strip having the same length as the trough, with thestrip 15 being etched in such a manner that after the trough 10 has beenmoulded and cut up into a plurality of brake linings, each liningcarries the necessary information.

When the inserts 6 are installed during moulding of the friction liningpreform, it is possible to slide a sheet between the preform and themould, said sheet having the inserts 6 pre-positioned thereon. Whenmoulding is completed, the sheet is withdrawn and the inserts remain inthe lining.

When the brake pad constitutes a single block that is made by moulding apowder mixture of friction material, it is possible to place the insertin the bottom of the mould or on the active face of the moulding piston.

Finally, the insert may be fixed on the friction lining during finalmachining of the lining. As can be seen in FIG. 8, the insert 6 may be aforce-fit in the bottom of a blind hole 20 of dimensions that make itimpossible to remove the insert. It is possible to install an insert 6in the form of a washer in a pre-existing hole 21, the insert being aforce-fit therein and coming to rest against a bearing surface 22 for arivet head for which the hole 21 is, in fact, provided. This embodimentis shown in FIG. 9.

What is claimed is:
 1. A brake lining for a vehicle brake, adapted tocooperate with a rotary part of the brake wherein the lining includes asubstantially planar friction face and an insert extending away fromsaid friction face, said insert having an identification surfacesubstantially parallel to said friction face, wherein said insert is notoxidizable and withstands temperatures greater than 200° C., saididentification surface being externally visible when the lining isinstalled in the vehicle brake, said identification surface providedwith indelible information identifying said lining.
 2. A brake liningaccording to claim 1, wherein said insert is of stainless steel.
 3. Abrake pad for a vehicle brake, the pad comprising a friction faceadapted to cooperate with a rotary part of the brake, and a supportportion adapted to cooperate with another brake component for taking upbraking torque, the friction face and the support portion being formedtogether by moulding, and wherein said support portion includes aninsert that is not oxidizable and that withstands temperatures greaterthan 200° C., said insert being provided in the form of a tongue, havingan identification surface located remote from said friction face andexternally visible when the pad is, installed in the vehicle brake, andwherein said identification surface projects away from and substantiallyparallel to said friction face and is provided with indelibleinformation identifying said brake pad.
 4. A brake lining or brake padaccording to claim 3, wherein the insert is of stainless steel.